It primarily consists of an area known as McNabney Marsh,[a] which lies alongside Interstate 680 near the Sacramento-San Joaquin Delta and between two large and active oil refineries.

The area provides habitat for a wide variety of waterfowl and shorebirds for resting and feeding.

[1] McNabney Marsh existed here before the area was visited by European explorers and missionaries in the early 1800s.

An upland area on the eastern border of the marsh was covered with eucalyptus and pepperwood trees, which provided the wood to build workers' houses.

More rarely, a lucky Park visitor may see the white-tailed kite, northern harrier, golden eagle, osprey, and peregrine falcon.